=== FIXED-KERNEL PANIC TEST (DF-5133) — same trigger, patched drm.ko ===
$ su -m nobody -c /tmp/panic_trigger
[panic_trigger] uid=65534 firing hw.dmabug.panic: kern_shutdown(dmabuf_fd, SHUT_RDWR) with dmabuf_fileops.fo_shutdown == NULL
dmabug: panic: uid=65534 dmabuf fd=3 f_ops=0xffffffff82654900 fo_shutdown=0xffffffff8062e5d0 (NULL => indirect call to 0)
dmabug: panic: calling kern_shutdown(3, SHUT_RDWR) -- same path as an unprivileged shutdown(2) on a prime fd
dmabug: panic: shutdown RETURNED (fo_shutdown set => fixed)
[panic_trigger] shutdown() returned 0 -- kernel survived (fo_shutdown present / fixed)
PANIC_RC=0
guest stayed up: vm.sh status => up